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Solar powered bidirectional EV charger with V2G

Funded by :

Gautham Ram, Dennis van der Meer, Pavol Bauer, Miro Zeman

Jos Schijffelen, Mike van den Heuvel, Menno Kardolus

Ross Baldick, Mahdi Kefayati

Eric van Voorden

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Goal

PV panels

EV @ workplace

EV charger

Solar carport

• Develop a highly efficient, modular, smart charging station for

electric vehicles with V2G that is powered by solar energy

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Motivation

* Images taken from the internet

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Solar powered

bidirectional

EV charger

Power

converter

Charging

algorithms

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System architecture

AC interconnection of EV and PV

PV Inverter

EV

PV

AC Inter – connection AC Grid

PV Inverter PV

EV Charger

EVEV

Charger

EV Charger

PV Inverter

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Charging of EV from PV : Our solution

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Integrated Design

IsolatedEV charger

(DC/DC)

10 kW MPC

PV panels10 kWp

AC Inter-connection

Inverter(DC/AC)

DC linkPV MPPT converter(DC/DC)

• Only one DC/AC converter Lower cost of converter

• DC-DC connection of EV-PV Improved efficiency

• Bi-directionality of DC/AC inverter Charge / V2G

G. R. Chandra Mouli, P. Bauer, and M. Zeman, “Comparison of system architecture and converter topology for a solar

powered electric vehicle charging station,” in 2015 9th International Conference on Power Electronics and ECCE Asia

(ICPE-ECCE Asia), 2015, pp. 1908–1915.

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4 Power Flows

IsolatedEV charger

(DC/DC)

10 kW MPC

PV panels10 kWp

AC Inter-connection

Inverter(DC/AC)

DC linkPV MPPT converter(DC/DC)

1. PV EV

2. Grid EV

3. EV Grid

4. PV Grid

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3x Power Density

• Higher power density

• Higher efficiency

• Bidirectional EV charging

EV

PV EV-PV

50cm x 50cm !!!

• SiC MOSFET, diode

• Interleaving of converters

• Powdered alloy inductors

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Power Converter Efficiency

• Power converter efficiency

• Peak Efficiency Grid ↔ EV : 95.4%

• Peak Efficiency PV → Grid : 96.4%

• Peak Efficiency PV → EV : 95.2%

IsolatedEV charger

(DC/DC)

10 kW MPC

PV panels10 kWp

AC Inter-connection

Inverter(DC/AC)

DC linkPV MPPT converter(DC/DC)

G. R. Chandra Mouli, J. Schijffelen, P. Bauer, and M. Zeman, “Design and Comparison of a 10kW Interleaved Boost Converter for PV Application Using Si and SiC Devices,” IEEE J. Emerg. Sel. Top. Power Electron.2016.

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60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10

Effi

cie

ncy

(%

)

Power (kW)

Eff(Grid->EV)

Eff(PV->Grid)

Eff(Grid->EV) Conventional

Eff(PV-> EV)

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CHAdeMO & CCS compatible

• Level 2, Mode 4, Type 4 - DC charging of up to 10kW

– CHAdeMO

– Combined charging system (CCS)

• 10kW*(8h) = 80kWh delivered to EV

• 390V EV successfully (dis)charged with 24A

G. R. Chandra Mouli, J. Schijffelen, M.v.d Heuvel, M.Kardolus, P. Bauer, and M. Zeman, “A 10kW Solar-Powered Bidirectional EV Charger Compatible with Chademo and COMBO”, IEEE Transactions on Power Electronics, under review

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Solar powered

bidirectional

EV charger

Power

converter

Charging

algorithms

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Energy Management System (EMS)

How can a EV fleet be optimally charged at workplace based on :

Energy prices

V2G

Charging from renewables (PV)

Distribution network limits

Multiplexing of EV

Regulation services

Net

her

lan

ds

Tex

as

Po

we

r (W

)0 Tv

a Tvd 24 Hour of day (h)

Smart chargingPV generationImmediate chargingAverage rate

xve(ar)

PEVr xe+

tdly

c t,v

v

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Energy Management System (EMS)

PV panels

EV charger(DC/DC)

Inverter(DC/AC)

Nchc Pc

conv ηc

conv

Pt,cPV Pt,c

feed

Pt,cdraw

xe+t,v

xrt,v

xe-t,v

EV & Chr Data

Energy Management System [EMS]

ISOpt

e(buy) pte(sell)

PDN+

t PDN-

t

Tav , T

dV

Bav , dv

xlbv , x

ubv

Bmaxv ,B

minv

ηchv , η

v2xv

Solar Forecastxe-

t,v , xe+

t,v , xrt,v

Bt,v

PPV(fc)t,c

CCH/V2X

KEVv,c N

connc

Cfcv , Cv2x

ACGrid

PV MPPT converter(DC/DC)

EV charger(DC/DC)

DC link

D. van der Meer; G. R. Chandra Mouli; G. Morales-Espana; L.R. Elizondo; P. Bauer, "Energy Management System with PV

Power Forecast to Optimally Charge EVs at the Workplace," in IEEE Transactions on Industrial Informatics

G. R. Chandra Mouli, R. Baldick, M.Kefayati, and P. Bauer, “Integrated PV Charging of EV Fleet Based on Dynamic Prices,

V2G and Offer of Reserves”, IEEE Transactions on Smart Grids, 2017, accepted

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Case Netherlands : Scenario 1

• EV car park with 4 EV connected to one EV-PV charger

• Energy prices from APX

Cnet = Cost(EV charging) – Sales (PV power)

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Case Netherlands : Scenario 2

• EV car park with

– 4 EV connected to one EV-PV charger

– 2 EV connected to second EV-PV charger

• Energy prices from APX

Cnet = Cost(EV charging) – Sales (PV power)

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Case Texas

• EV car park with 60 EV and 40 Chargers with solar

• Energy and regulation prices from ERCOT market

• 32% to 651% cost reduction

Charging Strategy AVERAGE

RATE UNCONTROLLED OPTIMAL

𝐶𝑎𝑟 , 𝐶𝑖𝑚𝑚, 𝐶𝑜𝑝𝑡 ($) 37.9 29.0 -15.3

𝐶%𝑖𝑚𝑚, 𝐶%

𝑜𝑝𝑡(%) 31.72 158.63

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• EV car park with 60 EV and 40 Chargers

• Energy and regulation prices from ERCOT market

• 32% to 651% cost reduction

Case Bidirectional

V2G

Energy prices

Regulation services

PV forecast

Case 1 No No Yes No

Case 2 No Yes No No

Case 3 No Yes Yes No

Case 4 No Yes No Yes

Case 5 Yes No Yes Yes

Case 6 No Yes Yes Yes

OPTIMAL Yes Yes Yes Yes

Case Texas

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Case Texas

• EV car park with 60 EV and 40 Chargers

• Energy and regulation prices from ERCOT market

• 32% to 651% cost reduction

Day Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 OPT

33 13.60 6.42 20.76 7.62 11.49 22.26 31.62

83 38.83 12.81 57.71 19.75 30.90 65.81 96.73

153 74.95 38.51 99.14 53.80 45.10 112.84 186.47

220 239.96 205.76 355.53 244.61 451.93 376.11 650.83

332 243.91 9.29 255.63 19.56 256.58 280.15 317.83

Mean 122.25 54.56 157.76 69.07 159.20 171.43 256.70

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PV charging of EV at workplace

www.youtube.com/watch?v=smrOCOLxBvg

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